The extent of the injury, as well as its origin, is unclear. However, Parsons's minutes have increased quite a bit this season, going up to 38 per game from 26 per game in 2011. The Rockets playing the second game of a back-to-back likely factors into the move, as well.
In Parsons's absence, the Rockets could start Daequan Cook, per Feigen, which would leave James Harden to guard former teammate Kevin Durant.
Parsons, a second-year pro out of Florida, is averaging 15.7 points, 7.0 rebounds and 3.5 assists per game this season. In the Rockets' 117-101 victory over the Toronto Raptors on Sunday, Parsons scored 18 points and pulled down seven boards.
The Rockets and Thunder will tip off at 7 p.m. CT. The game will be televised on NBA TV.